Formulations having an acidic pH, (i.e., <7), containing cationic components, such as cationic surfactants and salts thereof or active acidic components are commonly referred to as “low pH” formulations. Stable low pH viscous emulsion and gel formulations are difficult to obtain. Most commonly used thickeners are synthetic associative thickeners that are frequently anionic and hence typically are incompatible with the cationic component, especially quaternary ammonium salts, or are ineffective thickeners at low pH.
Consequently, the formulator of low pH compositions, especially emulsions, has a limited choice of either nonionic thickeners, such as nonionic surfactants, or cationic thickeners. Nonionic thickeners are uncharged and thus are assumed to be less reactive, but nonionics tend to inactivate preservatives and in some cases promote microbial growth. While some cationic polymeric rheology modifiers, such as hydrophobically modified aminoacrylate copolymers, are available commercially, their rheological properties are unpredictable, or aesthetically unsatisfactory.
US 2004/0241130 discloses multi-purpose polymers, methods and compositions, which is incorporated herein by reference.
US 2004/0052746 discloses multi-purpose polymers, methods and compositions, which is incorporated herein by reference.
U.S. Pat. No. 5,073,591 discloses polymeric thickeners and methods of producing the same, which is incorporated herein by reference.
U.S. Pat. No. 5,053,448 discloses polymeric thickeners and method of producing the same, which is incorporated herein by reference.
U.S. Pat. No. 4,892,916 discloses polymeric thickeners and their production, which is incorporated herein by reference.
U.S. Pat. No. 5,100,660 discloses thickened acidic aqueous compositions using cationic polymers, which is incorporated herein by reference.
US 2005/0119401 discloses the use of charged amphiphilic statistic polymers for thickening aqueous compositions, which is incorporated herein by reference.
U.S. Pat. No. 6,667,029 discloses stable, aqueous cationic hydrogels, which is incorporated herein by reference.
U.S. Pat. No. 4,542,175 discloses a method for thickening aqueous systems, which is incorporated herein by reference.
U.S. Pat. No. 6,326,430 discloses thickening agents for acidic aqueous compositions, which is incorporated herein by reference.
U.S. Pat. No. 6,271,192 discloses an associative thickener for aqueous fabric softener, which is incorporated herein by reference.
U.S. Pat. No. 5,011,978 discloses copolymers as thickeners and modifiers for latex systems, which is incorporated herein by reference.
U.S. Pat. No. 3,399,159 discloses cationic lattices and methods of preparing the same, which is incorporated herein by reference.
U.S. Pat. No. 5,990,233 discloses rheology modifiers for use in aqueous systems, which is incorporated herein by reference.
U.S. Pat. No. 5,840,789 discloses aqueous compositions thickened with acrylate-based polymeric rheology modifiers, which is incorporated herein by reference.
U.S. Pat. No. 6,465,416 discloses associative thickeners for aqueous fabric softener, which is incorporated herein by reference.
U.S. Pat. No. 6,025,431 discloses thickened personal care compositions, which is incorporated herein by reference.
Thus, there is an ongoing need and desire for a cationic compatible polymeric rheology modifier for low pH formulations.